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Dr. Aaron T. Byczynski

Internal Medicine (Internal Medicine Physician)

945 N 12th St
Milwaukee, WI 53233

Who else practices at this address →

Milwaukee County includes primary care (32% of residents) and mental health (34% of residents) shortage areas. About shortage areas

Call (414) 219-2000

At a glance

Years since graduation
3
In the NPI registry since
2023

The NPI date is when this clinician registered for a National Provider Identifier, the billing number used on health claims. It is not a license, graduation or board-certification date. What an NPI is

Education and training

  • 2023Medical school: West Virginia School of Osteopathic Medicine
  • 2023Registered with an NPI (national billing number; not a license date)

Undergraduate school, residency, fellowship, licensing exams and board certification aren’t in public federal data. Board certification can be confirmed with the certifying board (ABMS member boards for MDs, AOA boards for DOs).

Specialties and state licenses

  • Internal Medicine Physician primary
    WI license 81699

As reported to the NPI registry. To confirm a license is current, check the state medical board.

Map: Internal Medicine per capita by county →

Where they work

Hospitals

Medical groups

Hospitals this clinician lists with Medicare, and groups they bill Medicare through (Care Compare). Affiliation doesn’t mean they see patients at every location.

Other Internal Medicine clinicians in Milwaukee

Sources

NPI registry (CMS NPPES, November 2026; record last updated July 24, 2026), Medicare Care Compare, Medicare Physician & Other Practitioners (2024), Medicare Part D Prescribers (2024) and Open Payments (2025). Information is self-reported or billed data and may be out of date; call before visiting.

NPI 1457054942. Official NPI registry record (opens in a new tab). Clinicians can correct their information in NPPES; changes appear here after our next monthly update.